// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Slightly adapted for inclusion in V8.
// Copyright 2014 the V8 project authors. All rights reserved.

#ifndef V8_BASE_SAFE_CONVERSIONS_H_
#define V8_BASE_SAFE_CONVERSIONS_H_

#include <limits>

#include "src/base/safe_conversions_impl.h"

namespace v8 {
namespace base {

    // Convenience function that returns true if the supplied value is in range
    // for the destination type.
    template <typename Dst, typename Src>
    inline bool IsValueInRangeForNumericType(Src value)
    {
        return internal::DstRangeRelationToSrcRange<Dst>(value) == internal::RANGE_VALID;
    }

    // checked_cast<> is analogous to static_cast<> for numeric types,
    // except that it CHECKs that the specified numeric conversion will not
    // overflow or underflow. NaN source will always trigger a CHECK.
    template <typename Dst, typename Src>
    inline Dst checked_cast(Src value)
    {
        CHECK(IsValueInRangeForNumericType<Dst>(value));
        return static_cast<Dst>(value);
    }

    // saturated_cast<> is analogous to static_cast<> for numeric types, except
    // that the specified numeric conversion will saturate rather than overflow or
    // underflow. NaN assignment to an integral will trigger a CHECK condition.
    template <typename Dst, typename Src>
    inline Dst saturated_cast(Src value)
    {
        // Optimization for floating point values, which already saturate.
        if (std::numeric_limits<Dst>::is_iec559)
            return static_cast<Dst>(value);

        switch (internal::DstRangeRelationToSrcRange<Dst>(value)) {
        case internal::RANGE_VALID:
            return static_cast<Dst>(value);

        case internal::RANGE_UNDERFLOW:
            return std::numeric_limits<Dst>::min();

        case internal::RANGE_OVERFLOW:
            return std::numeric_limits<Dst>::max();

        // Should fail only on attempting to assign NaN to a saturated integer.
        case internal::RANGE_INVALID:
            UNREACHABLE();
        }

        UNREACHABLE();
    }

} // namespace base
} // namespace v8

#endif // V8_BASE_SAFE_CONVERSIONS_H_
